"sky is the limit."
You mean like "Jackie did it", or "the driver did it", "it was a hoax", or "Kennedy was an alien", or "GHWBush did it" Hilarious Jack.
Remember, "they" can do anything. And apparently, they did.
If we ask how did "they" do "A" or "B" or "C", we get the usual bogeyman of how awful Hoover and LBJ and Angleton were. How did "they" plant the rifle? "They just did". How did they know Oswald didn't have an alibi, that he wasn't with several people at the time of the shooting? "They just did."
"The sky's the limit" indeed.
This is conspiracy worldview first and then finding the evidence to support that view. When you have an event like the JFK assassination that has been studied to this degree - we literally have thousands of pieces of information on it - you can select a piece here and a piece there to support your conspiracy.
But it all has to start with a "the sky's the limit" view. That if it could be done then it simply was.